This Hubble Space Telescope view shows the crowded core of Messier 10, a globular star cluster in the constellation Ophiuchus. The cluster contains hundreds of thousands of stars, all packed into a ball-shaped region only a few dozen light-years in diameter. The bright yellowish stars in the image are red giants, which have puffed up as they near the ends of their lives. Such stars shine hundreds of times brighter than the Sun. [ESA/NASA/STScI]